I think I get it.
The Share button may be disabled because you have not finished setting up the Facebook application or are not compatible with what you use in the xcode / ios application.
- on Facebook Developer
In the settings of your application you need to add iOS and the site as platforms.
on the website platform you need to declare the URL of the website or mobile site: this will be used when someone clicks on your message from the computer. It should be a real site that you can access, perhaps the website of your application or a web page about your application included in the website. In this example, I will use
http://www.yourappwebsite.com
Once you do this, in the "Add Domains" field (in the section where you specify the namespace of names, etc.), you need to put the same domain that you are declaring as a website. This will be the only domain (s) allowed to host links and images of your OGStory. In this example
yourappwebsite.com
- Return to Xcode
You should have code defining the object you are sending, for example:
[FBGraphObject openGraphObjectForPostWithType:@"yourapp:yourobject" title:@"Roasted pumpkin seeds" image:@"http://www.yourappwebsite.com/yourpic.png" url:@"http://www.yourappwebsite.com" description:@"Crunchy pumpkin seeds roasted in butter and lightly salted."];
As you can see, the domain used for both the link and the image is listed earlier.
Your sharing button should now be enabled.
Hope this helps, ciao.